<accordion>
  <accordion-group is-open="isOpen">
    <accordion-heading>
      <i class="pull-right icon-plus-sign" ng-hide="isOpen"></i>
      <i class="pull-right icon-minus-sign" ng-show="isOpen"></i>
      <[heading]>
    </accordion-heading>
    <div angular-html-bind="content"></div>
  </accordion-group>
</accordion>
